Atrial fibrillation is the most common arrhythmia the general practitioner as well as the physician in the hospital has to deal with. Even if it is said to be benign, heart failure and embolism may be deleterious consequences of this arrhythmia. In this article we well discuss the management of this arrhythmia, taking into consideration the etiologic factors, the pathophysiology of atrial fibrillation and therapeutic aspects from cardioversion to prevention of embolism.